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T. A. EDISON. ELECTRIC INGANDESOENT LAMP.

Patented Oct. 24, 1882.;

IINrra *S raras ATENT Fries.

THOMAS A. EDISON, OF MENLO PARK, NEW JERSEY, ASSIGN'OR TO THE EDISONELECTRIC LIGHT COMPANY, OF NEW YORK, N. Y.

ELECTRIC INCANDESCENT LAMP.

SPECIFICATION forming part of Letters Patent No. 266,447, dated October24, 1832,

Application filed April 26, 1881.

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, of Menlo Park, in the county ofMiddlesex and State of New Jersey, have invented a new and usefulElectric Incandescent Lamp, (Case No. 306;) and I do hereby declare thatthe following is a full and exact description of the same, referencebeing had to the accompanying d rawings,and to the letters of referencemarked thereon.

The electric lamp usedin my system consists essentially of a filamentaryincandescing conductor of high resistance hermetically sealed in a glassvacuum-chamber.

In Letters Patent of the United States No. 230,255, granted to me, isshown and described a method or process of forming such a lamp. In thispresent case one object of the inven- 131011 is to show and describeanother method of forming such a lamp, while a second object is tofurnish an efficient leading-in wire having a clamping device formedintegral with it, as more fully hereinafter described and claimed.

In carrying the improved method referred to into practice the glasschamber is to be blown directly from the pot-glass. The blower takesupon the blowing-rod a sufficient quantity and blows the same into abulb, giving itjust sufficient motion to cause the bulb to slightlyelongate, so that its outer extremity shall be or about be semicircular,from which the sides taper gradually in straight or nearly straight orslightly curved lines to the end of the blowing-rod. The bulb so formedis then broken away at the tapered end sufficiently to leave an aperturelarge enough for the introduction therethrough into the bulb of thecarbon and its supports. Upon the semicircular end of the bulb a smallopening is made, and a tube is formed thereon either by drawing out thematerial thereat or by attaching thereto a separate piece of tubing toform the exhaust-tube of the completed lamp for attachment to theexhaust apparatus. A small piece of tubing is taken and an enlargementblown or formed therein of a diameter about equal to that of theaperture referred to as being made in the tapering or conical end of thebulb. The leading-in wires-2'. 0., the wires which pass into the lampand are to connect with the carbon- (No niodelJ are then laid in thistube, one end thereof being then brought to a nearly melting or weldingheat and clamped down by suitablemeans upon the wires, hermetically andfirmly sealing them in the glass of tube. which are preferably used areeach in three sections-viz, a central bit of platinum' for sealing intothe mass ot'.the glass with copper extremities, one leading away fromthe lamp, and one into the lamp for receiving and supporting the carbon.This latter section may be cut from flat or sheet copper, with anenlarged end, or it may be formed of a bit of wire one of whoseends isllattened out. This enlarged flattened portion is wrapped around orfolded upon the enlarged end of the carbon, securing itand makingelectrical contact therewith. This union may, if desired, beelectroplated. The carbon being secured to the leading-in wires and thensealed in the tube referred to, the carbon is introduced into the bulband the edge of the opening in the bulb and the enlarged portion of thetube sealed together at a welding heat. The lamp is then attached to theexhaust or vacuum apparatus by the exhaust-tube and the air exhaustedtherefrom. When the proper degree of exhaustion has been attained thelamp is sealed off by a welding and fusion of the exhausttube near tothe body of the bulb or lamp. This may be better understood by referenceto the drawings, in which a Figure 1 shows the bulb as blown and.attached to the blowing-rod; Fig.2, the bulb with its end broken 011'and the exhaust-tube attached to the bulb; Fig. 3, the supportingtube;Fig. 4, the lamp completed and sealed; Fig. 5, the lamp provided withmeans of attachment to a fixture; Fig. 6, a wire or blank for supportingthe carbon.

The blowing-rod B, indicated in broken lines, is dipped into the moltenor pot glass and a quantity sufficient for one bulb taken up thereon,which is then blown into the shape shown in Fig. 1. This shape issemicircular at its outer end, from whence the sides taper in straightor nearly straight lines to the smaller end, and this shapedistinguishes the electric lamp bulb or globe thus made from anyheretofore made. The part a is then cut The wires or broken from thebody of A, leaving an aperture at a- A is then heated at I), and a tube,I), formed thereon either by drawing out the material at b or byattaching thereto a separate piece of tubing. A piece of tubing, 1), istaken and an enlargement, (1, formed thereon of about the diameter or ofa slightly larger diameter thana. In this tube D are laid the leading-inwires 1, 2. These wires are each formed of three sections-a central one,2, of platinum, which is the portion to be in contact with the glass,with outer sections, 0 00,01 copper. The end i of the tube is thenbrought to a welding heat and squeezed firmly together, sealing theparts 2) p of l 2iirmly and hermetically therein. The carbon C is thenattached to the wire sections 0 0. One of these wires is shown in Fig.(3. They maybe cutot'the shape there shown from flat copper; but Iprefer to take a piece of wire, 0, and tlatten its end to form theenlargement c, which enlargement isfolded upon or wrapped around oneenlarged end of the carbon, making a tirm and secure contact therewithand support therelor. If desired, this union may then be plated. lfdesired, the neck or tube 1) may be made as the patent referred to, andthe wires and clamps therein shown used butfor economyl prefer the meansand methods herein shown. The tube and carbon being arranged in relationto each other, as shown in Fig. 3, the carbon is introduced within thebody of A and the edges (0 and (I brought to a welding heat and sealedtogether. The lamp is then attached by the exhaust-tube b to the vacuumapparatus, and when the proper degree of vacuum has been reached it issealed otf at I), the result being the lamp shown in Fig. 4. Means S forattaching the lamp to its support or fixture are then secured thereto,and the lamp is ready for the market.

\Vhat I claim is- 1. The method of manufacturing incandescent electriclamps,substantially as set forth, consisting in forming the iuclosingbulb or globe directly from molten or pot. glass, forming separately thesupporting tube or neck for the incainlcscent conductor, sealing thereinthe leading-in wires, attaching the carbon thereto, and thenhermetically unitingthcparts by a welding together prior to theexhaustion of the lamp, substantially as set forth.

2. A leading-in wire composed of a central platinum section for sealinginto the glass an outer section and an inner section, having a clampingdevice formed integral therewith, substantially as set forth.

This specification signed and witnessed this 21st day of April, 1881.

TIIOS. A. EDISON.

Witnesses:

WM. l-I. ALDEN, Jr., ll. W. SEELY.

